Department of Veterinary Pathobiology, School of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas, USA.
J Virol. 2024 Mar 19;98(3):e0185123. doi: 10.1128/jvi.01851-23. Epub 2024 Feb 14.
Recently, we identified the coxsackie and adenovirus receptor (CAR) as the entry receptor for rhesus enteric calicivirus (ReCV) isolate FT285 and demonstrated that co-expression of the CAR and the type B histo-blood group antigen (HBGA) is required to convert the resistant CHO cell line susceptible to infection. To address whether the CAR is also the functional entry receptor for other ReCV isolates and the requirement for specific HBGAs or other glycans, here we used a panel of recombinant CHO cell lines expressing the CAR and the type A, B, or H HBGAs alone or in combination. Infection studies with three diverse ReCV strains, the prototype GI.1 Tulane virus (TV), GI.2 ReCV-FT285, and GI.3 ReCV-FT7, identified that cell surface expression of the CAR is an absolute requirement for all three strains to promote susceptibility to infection, while the requirement for HBGAs varies among the strains. In addition to the CAR, ReCV-FT285 and TV require type A or B HBGAs for infection. In the absence of HBGAs, TV, but not Re-CV FT285, can also utilize sialic acids, while ReCV-FT7 infection is HBGA-independent and relies on CAR and sialic acid expression. In summary, we demonstrated strain-specific diversity of susceptibility requirements for ReCV infections and that CAR, type A and B HBGA, and sialic acid expression control susceptibility to infection with the three ReCV isolates studied. Our study also indicates that the correlation between HBGA binding and HBGAs required for infection is relatively high, but not absolute. This has direct implications for human noroviruses.IMPORTANCEHuman noroviruses (HuNoVs) are important enteric pathogens. The lack of a robust HuNoV cell culture system is a bottleneck for HuNoV cell culture-based studies. Often, cell culture-adapted caliciviruses that rapidly replicate in conventional cell lines and recapitulate biological features of HuNoVs are utilized as surrogates. Particularly, rhesus enteric caliciviruses (ReCVs) display remarkable similarities, including the primate host, clinical manifestation of gastroenteritis, genetic/antigenic diversity, and reliance on histo-blood group antigens (HBGAs) for attachment. While the HuNoV entry receptor(s) is unknown, the coxsackie and adenovirus receptor (CAR) has recently been identified as the ReCV entry receptor. Here, we identified the CAR, the type A and B HBGAs, and sialic acids as critical cell surface molecules controlling susceptibility to ReCV infections. The CAR is required for all ReCV isolates studied. However, the requirement for the different carbohydrate molecules varies among different ReCV strains. Our findings have direct implications for HuNoVs.
最近，我们发现柯萨奇病毒和腺病毒受体（CAR）是恒河猴肠道杯状病毒（ReCV）分离株 FT285 的进入受体，并证明 CAR 与 B 型组织血型抗原（HBGA）的共表达是将抵抗 CHO 细胞系转化为易感感染所必需的。为了解 CAR 是否也是其他 ReCV 分离株的功能性进入受体以及是否需要特定的 HBGA 或其他聚糖，我们在此使用一组单独或组合表达 CAR 和 A、B 或 H HBGA 的重组 CHO 细胞系。使用三种不同的 ReCV 株（原型 GI.1 图兰病毒（TV）、GI.2 ReCV-FT285 和 GI.3 ReCV-FT7）进行的感染研究表明，CAR 的细胞表面表达是所有三种菌株促进易感性感染的绝对要求，而对 HBGA 的要求因菌株而异。除了 CAR，ReCV-FT285 和 TV 需要 A 型或 B 型 HBGA 才能感染。在没有 HBGA 的情况下，TV 而不是 ReCV FT285，也可以利用唾液酸，而 ReCV-FT7 的感染则与 HBGA 无关，依赖于 CAR 和唾液酸的表达。总之，我们证明了 ReCV 感染的敏感性要求存在菌株特异性多样性，并且 CAR、A 型和 B 型 HBGA 以及唾液酸表达控制着三种 ReCV 分离株感染的易感性。我们的研究还表明，HBGA 结合与感染所需的 HBGA 之间的相关性相对较高，但并非绝对。这对人类诺如病毒（HuNoVs）有直接影响。
重要性：人类诺如病毒（HuNoVs）是重要的肠道病原体。缺乏强大的 HuNoV 细胞培养系统是 HuNoV 细胞培养研究的瓶颈。通常，在常规细胞系中快速复制并重现 HuNoVs 生物学特征的细胞培养适应的杯状病毒被用作替代品。特别是，恒河猴肠道杯状病毒（ReCV）表现出显著的相似性，包括灵长类动物宿主、肠胃炎的临床表现、遗传/抗原多样性以及对组织血型抗原（HBGA）的依赖用于附着。虽然 HuNoV 的进入受体（s）尚不清楚，但最近已确定柯萨奇病毒和腺病毒受体（CAR）是 ReCV 的进入受体。在这里，我们确定了 CAR、A 型和 B 型 HBGA 以及唾液酸作为控制 ReCV 感染易感性的关键细胞表面分子。CAR 是所有研究的 ReCV 分离株所必需的。然而，不同碳水化合物分子的要求因不同的 ReCV 菌株而异。我们的发现对 HuNoVs 有直接影响。
